ISHS Acta Horticulturae 779: International Symposium on Growing Media
ACIDIFICATION OF COMPOSTS FROM AGRICULTURAL WASTES TO PREPARE NURSERY POTTING MIXTURES |
| Authors: | C. Carrión, M. Abad, F. Fornes, V. Noguera, R. Puchades, A. Maquieira, S. Botella, R. García |
| Keywords: | vegetable crop wastes, acidification efficiency, elemental sulfur, ferrous sulfate, microbial ecology |
| Abstract:
The effects of powdered elemental sulfur (S0) and ferrous sulfate (FeSO4.7H2O) on the pH of three alkaline composts prepared with residual vegetable crop biomass (melon, C1; pepper, C2 and zucchini, C3) were investigated. Composts reacted differently to the application of the amendments, the acidification efficiency averaging 43%, 50% and 36% for C1, C2 and C3, respectively. S0 was more efficient than FeSO4.7H2O for lowering the pH, and a saturation-like effect was found within the range of amendment rates studied. The pH decrease ranged from 0.24 to 3.03 units. This pH reduction was paralleled by an increase in compost salinity, especially with S0. pH declined slowly and gradually with S0, whereas FeSO4.7H2O decreased pH soon after its application, followed by a progressive increase and subsequent stabilization. When S0 was added to the compost, the sulfur-oxidizing bacteria population increased from 107 to 1010 CFU/g during the first 50 days of incubation, followed by a significant decrease. This initial increase in bacterial population paralleled the pH decrease observed. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
